Implantable myocardial ischemia detection, indication and action technology

• US 6,501,983 B1
• Filed: 08/06/1999
• Issued: 12/31/2002
• Est. Priority Date: 08/07/1998
• Status: Expired due to Term

• Current Assignee: Infinite Biomedical Technologies, LLC
• Original Assignee: Infinite Biomedical Technologies, LLC
• Inventors: Thakor, Nitish V., Natarajan, Ananth
• Primary Examiner(s): Shaver, Kevin
• Assistant Examiner(s): Natnithithadha, Navin
• Application Number:
  US09/369,576
• Time in Patent Office: 1,243 Days
• Field of Search: 600/481, 600/483, 600/485, 600/486, 600/488, 600/508, 600/509, 600/510, 600/511, 600/512, 600/513, 600/514, 600/515, 600/516, 600/517, 600/518, 600/519, 600/520, 600/521, 600/522, 600/523, 600/524, 600/525, 600/526, 600/527
• US Class Current: 600/517
• CPC Class Codes: A61B 5/287 Holders for multiple electrodes, e.g. electrode catheters for electrophysiological study [EPS]
• CPC Class Codes: A61B 5/349 Detecting specific parameters of the electrocardiograph cycle
• CPC Class Codes: A61B 5/4836 Diagnosis combined with treatment in closed-loop systems or methods A61B5/0036 takes precedence
• CPC Class Codes: A61B 5/726 using Wavelet transforms
• CPC Class Codes: A61M 5/1723 using feedback of body parameters, e.g. blood-sugar, pressure measurement of body parameters A61B5/00
• CPC Class Codes: A61N 1/3627 for treating a mechanical deficiency of the heart, e.g. congestive heart failure or cardiomyopathy
• CPC Class Codes: A61N 1/365 controlled by a physiological parameter, e.g. heart potential evoked response A61N1/371
• CPC Class Codes: A61N 1/37 Monitoring; Protecting
• CPC Class Codes: A61N 1/3962 in combination with another heart therapy

Abstract

One embodiment enables detection of MI/I and emerging infarction in an implantable system. A plurality of devices may be used to gather and interpret data from within the heart, from the heart surface, and/or from the thoracic cavity. The apparatus may further alert the patient and/or communicate the condition to an external device or medical caregiver. Additionally, the implanted apparatus may initiate therapy of MI/I and emerging infarction.

Claims

1. A method comprising:

monitoring the heart for evidence of myocardial ischemia/infarction (MI/I) using a device implanted into a subject, the device including at least one lead positioned at least partially in at least one of the heart and the vascular system; and

alerting the subject upon detection of MI/I using a signal generated by the implanted device.

2. A method as in claim 1, wherein the detecting MI/I comprises:

sensing an electrogram signal; and

determining the occurrence of MI/I based on the electrogram signal.

3. A method as in claim 1, wherein the detecting MI/I comprises:

positioning a plurality of leads and sensors in the subject;

transmitting data from the sensors to a microprocessor; and

determining whether an MI/I event has occurred.

4. A method as in claim 3, wherein the alerting the subject comprises sending the signal to a device external of the subject.

5. A method as in claim 1, further comprising sending a signal to a device external of the subject.

6. A method as in claim 1, further comprising initiating therapy within the subject after detecting MI/I.

7. A method as in claim 1, further comprising providing a supply of a medicine as part of the device implanted into the subject and supplying a dose of the medicine to the subject after detecting MI/I.

22. A method as in claim 3, wherein the positioning a plurality of leads comprises positioning the leads so that the sensors are configured in an orthogonal pattern.

23. A method as in claim 3, wherein the positioning a plurality of leads comprises placing the leads to form sensing configurations in a plurality of regions in the heart that enhance sensitivity to MI/I.

38. A method as in claim 1, wherein the detecting myocardial ischemia includes separating a normal from an ischemic-electrogram signal, the method comprising analyzing the electrogram signal using an analysis selected from the group consisting of (1) an electrogram waveform analysis for temporal features, (2) an electrogram waveform analysis using time-domain signal analysis methods, (3) an electrogram waveform analysis using a frequency domain method such as FFT and filtering, and (4) an electrogram waveform analysis using a combined time and frequency analysis method.

39. A method as in claim 38, wherein the analyzing the electrogram signal comprises using an electrogram waveform analysis for at least one temporal feature selected from the group consisting of peaks and inflections.

43. A method as in claim 1, wherein the device comprises a portion of an implanted apparatus selected from the group consisting of a pacemaker, a cardioverter, a defibrillator, a cardiac assist device, and an infusion pump.

50. A method as in claim 1, wherein the alerting the subject is carried out using an electromagnetic link to an external device worn by the subject.

51. A method as in claim 1, wherein alerting the subject is carried out by activating a device selected from the group consisting of an external pager and external alarm.

52. A method as in claim 1, further comprising alerting a person other than the subject upon detection of a MI/I a method selected from the group consisting of electrical communication via RF links, modulation of a magnetic field signal, electromagnetic transmission, auditory transmission, digital encoding and transmission of a signal, and analog modulation and transmission of a signal.

106. A method as in claim 3, wherein the positioning a plurality of leads comprises positioning the leads in an internal Einthoven triangle placement.

107. A method as in claim 1, wherein the detecting myocardial ischemia comprises:

using at least one sensor selected from the group consisting of a cavitary pressure sensor, a myocardial cavitary volume sensor, a blood pO2 sensor, a blood pH sensor, a blood lactate sensor, and a tissue impedance sensor;

wherein the sensor comprises a portion of the device implanted into the subject; and

wherein the sensor is capable of distinguishing a myocardial ischemia condition from a non-myocardial ischemia condition.

108. A method as in claim 38, wherein the analyzing the electrogram signal comprises using a frequency domain method selected from the group consisting of fast Fourier transform and filtering.

109. A method as in claim 38, wherein the analyzing the electrogram signal comprises using a combined time and frequency analysis selected from the group consisting of joint time frequency distributions and wavelet analysis.

110. A method as in claim 1, wherein the alerting signal comprises a signal selected from the group consisting of an electrical signal, a magnetic signal, an electromagnetic signal, and an auditory signal.

111. A method as in claim 1, wherein the alerting the subject is carried out by electrical stimulation of the subject.

112. A method as in claim 1, wherein the alerting the subject is carried out by a communication selected from the group consisting of auditory communication and vibratory communication.

8. A method for monitoring the heart of a subject for MI/I inside of the subject, comprising:

implanting into a subject'"'"'s chest a container including circuitry and a microprocessor;

providing a plurality of sensors electrically connected to the circuitry;

positioning at least one sensor in the subject'"'"'s cardiovascular system; and

determining whether MI/I has occurred.

9. A method as in claim 8, wherein the plurality of sensors includes at least one sensor from a group consisting of electrical, mechanical and hemodynamic sensors.

10. A method as in claim 9, wherein the microprocessor includes at least one algorithm for interpreting a signal generated by the at least one sensor and determining whether MI/I has occurred.

11. A method as in claim 9, wherein the container is implanted subcutaneaously.

12. A method as in claim 9, wherein the container is implanted with intracavitory connections.

13. A method as in claim 9, wherein the container is implanted with epicardial connections.

14. A method as in claim 9, wherein the container is implanted with electrical access to a plurality of chambers of the heart.

18. A method as in claim 8, wherein at least one sensor is mounted on the container.

19. A method as in claim 8, wherein the sensors are attached to leads extending from the container, the method further comprising positioning leads at three orthogonal locations on the container.

20. A method as in claim 8, wherein the sensors are positioned in a configuration selected from the group consisting of orthogonal, Einthoven triangle, and chest lead configuration.

53. A method as in claim 8, further comprising communicating between the implanted container and a device external to the subject, comprising positioning the external device adjacent to the torso of the subject.

54. A method as in claim 8, further comprising communicating between the implanted container and a device external to the subject.

56. A method as in claim 8, further comprising communicating between the implanted container and a device external to the subject, wherein the communicating is carried out using radiotelemetry.

57. A method as in claim 8, further comprising communicating between the implanted container and a device external to the subject, wherein the communicating is carried out using links between the implanted container and a computer system.

59. A method as in claim 54, wherein the device external to the subject comprises a device selected from the group consisting of a telephone and a pager.

113. A method as in claim 9, wherein the container is fully implanted within the blood vessels and cavity of the heart.

114. A method as in claim 9, wherein the container is implanted with access to intracavitary blood.

115. A method as in claim 9, wherein the container is implanted with access to intravascular blood.

116. A method as in claim 54, wherein a modem protocol is used to communicate between the implanted container and a telephone.

117. A method as in claim 8, further comprising communicating between the implanted container and a device external to the subject, wherein the communicating is carried out using links between the implanted container and a health care provider'"'"'s computer system.

118. A method as in claim 8, further comprising communicating between the implanted container and a device external to the subject, wherein the device external to the subject includes an emergency care network.

15. A method for monitoring the heart of a subject for MI/I inside of the subject. comprising:

implanting into a subject'"'"'s chest a container including circuitry and a microprocessor;

providing a plurality of sensors electrically connected to the circuitry;

positioning at least one sensor in or on the heart of the subject; and

determining whether MI/I has occurred;

wherein the plurality of sensors includes at least one sensor from a group consisting of electrical, mechanical and hemodynamic sensors; and

wherein the container is fully implanted within the blood vessels and cavity of the heart.

16. A method for monitoring the heart of a subject for MI/I inside of the subject, comprising:

implanting into a subject'"'"'s chest a container including circuitry and a microprocessor;

providing a plurality of sensors electrically connected to the circuitry;

positioning at least one sensor in or on the heart of the subject; and

determining whether MI/I has occurred;

wherein the plurality of sensors includes at least one sensor from a group consisting of electrical, mechanical and hemodynamic sensors; and

wherein the container is implanted with access to intracavitary blood.

17. A method for monitoring the heart of a subject for MI/I inside of the subject, comprising:

implanting into a subject'"'"'s chest a container including circuitry and a microprocessor;

providing a plurality of sensors electrically connected to the circuitry;

positioning at least one sensor in or on the heart of the subject; and

determining whether MI/I has occurred;

wherein the plurality of sensors includes at least one sensor from a group consisting of electrical, mechanical and hemodynamic sensors; and

wherein the container is implanted with access to intravascular blood.

21. A method comprising:

monitoring the heart for evidence of myocardial ischemia/infarction (MI/I) using a device implanted into a subject;

alerting the subject upon detection of MI/I using a signal generated by the implanted device;

wherein the detection of MI/I comprises positioning a plurality of leads and sensors in the subject, transmitting data from the sensors to a microprocessor, and determining whether an MI/I event has occurred; and

wherein the positioning a plurality of leads comprises positioning the leads in an internal Einthoven triangle placement.

24. A method for monitoring a heart in a subject for evidence of MI/I comprising:

implanting a container including circuitry and a microprocessor in the subject; and

providing a plurality of leads extending from the container, wherein at least one lead extends to a position inside of the heart.

25. A method as in claim 24, further comprising positioning a plurality of leads in a plurality of heart chambers.

26. A method as in claim 24, further comprising positioning a plurality of leads to provide electrical access to a plurality of chambers of the heart.

27. A method as in claim 24, further comprising positioning routing at least one lead inside a heart cavity selected from the group consisting of the atrial and the ventricular.

28. A method as in claim 24, further comprising positioning at least one lead to provide electrical access to epicardial regions of the heart.

29. A method as in claim 24, further comprising positioning at least one lead to provide electrical access to thoracic regions surrounding the heart.

30. A method as in claim 24, further comprising positioning at least one lead to provide electrical access to subcutaneous regions adjacent in the vicinity of the heart.

31. A method as in claim 24, further comprising positioning multiple electrically conductive sensor elements on at leaf one lead.

32. A method as in claim 24, further comprising positioning multiple sensor elements selected from the group consisting of unipolar elements and bipolar elements on at least one lead.

33. A method as in claim 24, further comprising mounting at least one sensor element on the container.

34. A method as in claim 24, further comprising:

transmitting at least one signal through at least one of the leads to the circuitry;

amplifying the signal;

filtering the signal; and

converting the signal from an analog signal to a digital signal.

35. A method as in claim 34, wherein a plurality of signals are transmitted through a plurality of leads and are delivered to the circuitry, further comprising feeding the signals to a multiplexer, converting the signal from an analog signal to a digital signal, and delivering the signal to the microprocessor.

44. A method as in claim 24, further comprising a plurality of sensors coupled to the plurality of leads, and detecting the location of a MI/I site by sensing signals from sensors located at different position within the subject and analyzing the changes in the signal at the different positions.

45. A method as in claim 44, wherein the analyzing comprises calculation of cardiac dipoles of the MI/I site by dipole projection.

46. A method as in claim 44, wherein a plurality of the leads are positioned orthogonal to each other.

47. A method as in claim 44, wherein the detecting the location is determined using leads selected from the group consisting of orthogonal leads, Einthoven triangle leads, chest leads, and endocardial cavita leads.

36. A method comprising:

monitoring the heart for evidence of myocardial ischemia/infarction (MI/I) using a device implanted into a subject; and

alerting the subject upon detection of MI/I using a signal generated by the implanted device;

wherein the detecting myocardial ischemia comprises using at least one sensor selected from the group consisting of a cavitary pressure sensor, a myocardial cavitary volume sensor, a blood pO2 sensor, a blood pH sensor, a blood lactate sensor, and a tissue impedance sensor;

wherein the sensor comprises a portion of the device implanted into the subject; and

wherein the sensor is capable of distinguishing a myocardial ischemia condition from a non-myocardial ischemia condition.

37. A method as in claim 36, wherein at least one sensor comprises a myocardial cavitary volume sensor that operates using conductance.

40. A method comprising:

monitoring the heart for evidence of myocardial ischemia/infarction (MI/I) using a device implanted into a subject; and

alerting the subject upon detection of MI/I using a signal generated by the implanted device;

wherein the detection of myocardial ischemia includes separating a normal from an ischemic electrogram signal, and includes analyzing the electrogram signal using a frequency domain method selected from the group consisting of fast Fourier transform and filtering.

41. A method comprising:

monitoring the heart for evidence of myocardial ischemia/infarction (MI/I) using a device implanted into a subject; and

alerting the subject upon detection of MI/I using a signal generated by the implanted device;

wherein the detection of myocardial ischemia includes separating a normal from an ischemic electrogram signal, and includes analyzing the electrogram signal using a combined time and frequency analysis selected from the group consisting of joint time frequency distributions and wavelet analysis.

42. A method comprising:

monitoring the heart for evidence of myocardial ischemia/infarction (MI/I) using a device implanted into a subject; and

alerting the subject upon detection of MI/I using a signal generated by the implanted device, wherein the implanting device directly alerts the subject using a signal selected from the group consisting of an electrical signal, a magnetic signal, an electromagnetic signal, and an auditory signal.

48. A method comprising:

monitoring the heart for evidence of myocardial ischemia/infarction (MI/I) using a device implanted into a subject; and

alerting the subject upon detection of MI/I using a signal generated by the implanted device, wherein the alerting the subject is carried out by electrical stimulation of the subject.

49. A method comprising:

monitoring the heart for evidence of myocardial ischemia/infarction (MI/I) using a device implanted into a subject; and

alerting the subject upon detection of MI/I using a signal generated by the implanted device, wherein the alerting the subject is carried out by a communication generated by the implanted device, the communication selected from the group consisting of auditory communication and vibratory communication.

55. A method for monitoring the heart of a subject for MI/I inside of the subject, comprising:

implanting into a subject'"'"'s chest a container including circuitry and a microprocessor;

providing a plurality of sensors electrically connected to the circuitry;

positioning at least one sensor in or on the heart of the subject;

determining whether MI/I has occurred; and

communicating between the implanted container and a device external to the subject;

wherein a modem protocol is used to communicate between the implanted container and a telephone.

58. A method for monitoring the heart of a subject for MI/I inside of the subject, comprising:

implanting into a subject'"'"'s chest a container including circuitry and a microprocessor;

providing a plurality of sensors electrically connected to the circuitry;

positioning at least one sensor in or on the heart of the subject;

determining whether MI/I has occurred; and

comprising communicating between the implanted container and a device external to the subject, wherein the communicating is carried out using links between the implanted container and a health care provider'"'"'s computer system.

60. A method for monitoring the heart of a subject for MI/I inside of the subject, comprising:

implanting into a subject'"'"'s chest a container including circuitry and a microprocessor;

providing a plurality of sensors electrically connected to the circuitry;

positioning at least one sensor in or on the heart of the subject;

determining whether MI/I has occurred; and

communicating between the implanted container and a device external to the subject, wherein the device external to the subject includes an emergency care network.

61. A method of manufacturing an implantable device elected from the group consisting of pacemakers, cardio-defibrillators, atrial defibrillators, ventrical defibrillators, cardiac assist devices, and drug infusion devices, the method including incorporating into the implantable device circuitry for monitoring the occurrence of a MI/I in a subject and providing a signal indicating the occurrence of a MI/I, the method further including incorporating into the implantable device at least one lead adapted to extend into the subject'"'"'s vascular system.

62. A method as in claim 61, further comprising delivering the signal to a device external to the implantable device.

63. A method as in claim 61, further comprising alerting the subject of the occurrence of a MI/I.

119. A method as in claim 61, wherein the at least one lead is adapted to extend into the subject'"'"'s heart.

64. An apparatus for detecting MI/I in a subject, comprising:

an implantable container;

at least one lead adapted for insertion into the heart;

at least one sensor adapted for insertion into the heart; and

a microprocessor in the container to analyze data from the at least one sensor.

65. An apparatus as in claim 64, further comprising circuitry to transmit a signal from the sensor to the microprocessor.

66. An apparatus as in claim 65, further comprising means to alert the subject after detecting MI/I.

67. An apparatus as in claim 65, further comprising means to communicate with at least one device external to the subject.

68. An apparatus as in claim 64, further comprising means for initiating therapy after detecting MI/I.

69. An apparatus as in claim 65, further comprising a supply of at least one drug adapted for insertion into the body, wherein the supply is released upon receiving a signal from the microprocessor.

70. An apparatus as in claim 64, wherein the container comprises a can that is adapted to fit inside of the subject'"'"'s heart.

71. An apparatus as in claim 64, wherein the container comprises a can comprising the shape of an implanted device selected from the group consisting of a pacemaker, a cardioverter, a defibrillator, a cardiac assist device, and an infusion pump.

72. An apparatus as in claim 64, wherein the container comprises a can having a triangular shape.

73. An apparatus as in claim 64, wherein the container comprises a can shaped in the form of a pouch adapted to surround a portion of a heart.

74. An apparatus as in claim 64, wherein the container comprises a can shaped to include three orthogonal locations for mounting electrodes.

75. An apparatus as in claim 64, wherein the container comprises a can shaped to include locations to permit Einthoven triangle electrode placement.

76. An apparatus as in claim 64, wherein the container comprises a can, wherein at least one sensor is mounted on the can.

77. An apparatus as in claim 64, further comprising an electrode, wherein the sensor is attached to the lead through the electrode.

78. An apparatus as in claim 64, wherein the sensor includes an electrode coupled to the lead.

79. An apparatus as in claim 78, comprising a plurality of electrodes adapted for insertion into the heart in a variety of locations.

80. An apparatus as in claim 64, wherein the lead is configured to transmit electrogram signals from at least two locations selected from the group consisting of atrial heart cavity locations, ventricular heart cavity locations, epicardial heart locations, thoracic locations surrounding a heart, and subcutaneous locations adjacent to a heart.

81. An apparatus as in claim 64, wherein at least one lead includes a plurality of sensors coupled thereto.

82. An apparatus as in claim 64, wherein at least one lead includes a plurality of electrically conductive sensor elements thereon.

83. An apparatus as in claim 64, wherein at least one lead includes multiple unipolar elements.

84. An apparatus as in claim 64, wherein at least one lead includes multiple bipolar elements.

85. An apparatus as in claim 64, wherein the container acts as a reference for electrical common.

86. An apparatus as in claim 64, wherein at least one sensor is mounted on the container and at least one sensor is mounted to a lead a distance away from the container.

87. An implantable apparatus for monitoring a subject for MI/I comprising:

a hermetically sealed container;

circuitry disposed within the container;

an analog to digital converter disposed within the container;

a logic device disposed within the container; and

a feed-through interface between at least one lead extending from the container and the circuitry.

88. An apparatus as in claim 87, wherein the logic device comprises a microprocessor.

89. An apparatus as in claim 87, further comprising at least one amplifier disposed within the container.

90. An apparatus as in claim 87, further comprising at least one filter disposed within the container.

91. An apparatus as in claim 87, further comprising at least one sensor to recognize a MI/I condition, the sensor being coupled to a lead.

92. An apparatus as in claim 91, wherein the sensor comprises a sensor selected from the group consisting of a blood pO2 sensor, a blood pH sensor, a blood lactate sensor, a blood temperature sensor, and a tissue impedance sensor.

93. An apparatus as in claim 87, wherein the monitoring for MI/I includes separating normal from ischemic electrogram signals by means to perform electrogram waveform analysis for temporal features including peaks and inflections.

94. An apparatus as in claim 87, wherein the monitoring for MI/I includes separating normal from ischemic electrogram signals by means to perform electrogram waveform analysis using time-domain signal analysis.

95. An apparatus as in claim 87, wherein the monitoring for MI/I includes separating normal from ischemic electrogram signals by means to perform electrogram waveform analysis using frequency domain methods.

96. An apparatus as in claim 87, wherein the monitoring for MI/I includes separating normal from ischemic electrogram signals by means to perform electrogram waveform analysis using combined time and frequency analysis.

97. An apparatus as in claim 87, wherein the monitoring for MI/I includes separating normal from ischemic electrogram signals by means to analyze changes in depolarization and repolarization.

98. An apparatus as in claim 87, wherein the monitoring for MI/I includes means for detecting a MI/I signal by determining its temporal features synchronous to the Q, R, S, and T waves in an electrogram signal.

120. A method as in claim 87, wherein at least one lead extending from the container is adapted to be positioned in the subject'"'"'s heart.

121. A method as in claim 87, wherein at least one lead extending from the container is adapted to be positioned in the subject'"'"'s vascular system.

122. A method as in claim 87, wherein the container is positioned within the subject'"'"'s cardiovascular system.

99. An apparatus for detecting MI/I in a subject, comprising:

means for detecting MI/I; and

means for generating a signal to alert the subject about the MI/I;

wherein the means for detecting and the means for generating the signal are adapted to be implantable into at least one of the heart and vascular system in the subject.

100. An apparatus for detecting MI/I in a subject, comprising:

an implantable container;

at least one lead adapted for insertion into the heart and electrically connected to circuitry in the container;

at least one sensor coupled to the at least one lead and adapted for insertion into the heart;

a microprocessor in the container to analyze data from the at least one sensor; and

a transmitter.

101. An apparatus as in claim 100, wherein the transmitter comprises a device selected from the group consisting of an RF transmitter, an electrical transmitter, and an electromagnetic transmitter.

102. An apparatus as in claim 100, wherein the transmitter comprises means to transmit a signal to the subject.

103. An apparatus as in claim 102, wherein the transmitter comprises means to transmit a signal to a device external from the subject.

104. An apparatus as in claim 100, wherein the implantable container is adapted to fit within a heart cavity.

105. An apparatus as in claim 100, wherein the implantable container is adapted to fit transvenously within a subject.